Distributed semiconductor device methods, apparatus, and systems

ABSTRACT

Some embodiments include a device having a number of memory cells and associated circuitry for accessing the memory cells. The memory cells of the device may be formed in one or more memory cell dice. The associated circuitry of the device may also be formed in one or more dice, optionally separated from the memory cell dice.

FIELD

The present disclosure relates generally to semiconductor devices,including semiconductor devices in integrated circuit packages.

BACKGROUND

Semiconductor devices such as memory devices and processors are widelyused in computers and electronic products. A memory device often hasmany memory cells to store data. The memory device may also includeassociated support circuitry to access the memory cells and to providecommunication with other devices. In some memory devices, the memorycells and the support circuitry are formed as a single semiconductor dieenclosed in an integrated circuit package or chip.

For some electronic products, to increase data storage capacity for agiven die size, features in the device (e.g., transistors and connectingelements) may be shrunk to create more room for additional memory cells.Additional conductive lines in the device may also be created toaccommodate the additional memory cells. Since the die may remain thesame size, the additional conductive lines may cause the total number ofconductive lines to become dense.

Dense conductive lines in the device may increase capacitive loading,capacitive coupling, or both, leading to possible poor deviceperformance. Moreover, shrinking feature size in semiconductor devicesmay be limited by a minimum achievable dimension. Thus, in devices wherethe features are already at the minimum achievable dimension, furtherreduction in the dimension of the device features may be unachievable.Increasing data storage density in these devices may be difficult.Therefore, alternative fabrication and packaging techniques may beneeded to achieve increased data storage capacity in semiconductordevices.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a memory device in which portions of thememory device may be distributed in multiple dice according to anembodiment of the invention.

FIG. 2 shows a partial cross section of an integrated circuit (IC)package having a memory device with portions of the memory device beingdistributed in a stack of two dice according to an embodiment of theinvention.

FIG. 3 shows a partial cross section of an IC package having a memorydevice with bonding wires arranged according to an embodiment of theinvention.

FIG. 4 shows a partial cross section of a memory device having a stackof more than two dice according to an embodiment of the invention.

FIG. 5 and FIG. 6 show different views of a wafer with dice having firstportions of memory devices according to an embodiment of the invention.

FIG. 7 and FIG. 8 show different views of a wafer with dice havingsecond portions of memory devices according to an embodiment of theinvention.

FIG. 9 shows an exploded view of a wafer stack having dice with asubstantially equal size.

FIG. 10 through FIG. 20 show processes of forming memory devices from awafer stack of two wafers according to an embodiment of the invention.

FIG. 21 and FIG. 22 show processes of forming a memory device from awafer stack of more than two wafers according to an embodiment of theinvention.

FIG. 23 through FIG. 26 show processes of forming a memory device frommultiple wafer stacks according to an embodiment of the invention.

FIGS. 27 and 28 show processes of forming a device from a wafer stack inwhich at least one wafer of the wafer stack includes multiple circuitsin each die according to an embodiment of the invention.

FIG. 29 is a block diagram of an IC package having a memory device and aprocessor according to an embodiment of the invention.

FIG. 30 is a block diagram of a system according an embodiment of theinvention.

DETAILED DESCRIPTION OF DRAWINGS

FIG. 1 shows a block diagram of a memory device 100. Memory device 100may comprise a dynamic random access memory (DRAM) device, static randomaccess memory (SRAM) device, flash memory device, and/or other memorydevices. In addition to the memory device circuit elements shown, oneskilled in the art will readily recognize that memory device 100 mayinclude other circuit elements. These other circuit elements of memorydevice 100 are omitted from FIG. 1 for clarity.

Memory device 100 may include a number of device portions, such asdevice portions 101, 102, 103 and 104. Device portion 101 includesmemory array 110 having memory cells 121 arranged in rows and columns,word lines 115, and bit lines 125. In some embodiments, memory array 110may include additional circuitry (e.g., source followers) for accessingmemory cells 121 from outside memory device 100 so that memory cells 121may be tested.

Device portion 103 includes a sense amplifier 122, which responds tosignals on bit lines 125 to determine the values of data transferred toand from memory cells 121.

Device portion 104 includes an input and output unit 134 to transferdata between memory cells 121 and data lines 136. Data signals DQ0through DQN on lines 136 represent data transferred to and from memorycells 121. Memory device 100 may include one or more strobe lines 137 totransfer strobe signals DQS. The DQS signals may represent timinginformation associated with the DQ0 through DQN signals.

Device portion 102 includes a row decoder 124, a column decoder 126, anda control unit 138. Row and column decoders 124 and 126 respond toaddress signals A0 through AX provided on address lines 128 to accessmemory cells 121 via word lines 115 and bit lines 125. The signals A0through AX may carry information to select row addresses and columnaddresses of memory cells 121. Control unit 138 controls the operationsof memory device 100 based on control signals on control lines 142.Examples of the control signals include a row address strobe signalRAS*, a column address strobe signal CAS*, a write select signal WE*, achip select signal CS*, and a clock signal CLK. The operations of memorydevice 100 include a write operation and a read operation.

The write operation transfers data from data lines 136 to memory cells121. The read operation transfers data from memory cells 121 to datalines 136. Address signals A0 through AX provide addresses of the memorycells that are being accessed in the read or write operation.

As shown in FIG. 1, device portions 101 through 104 may include one ormore circuit elements of device 100. For example, device portion 101 mayinclude memory cells and associated connections for word lines 115 andbit lines 125. In another example, device portion 102 may includecontrol unit 138 and row and column decoders 124 and 126. FIG. 1 showsmemory device 100 with four device portions 101 through 104 as anexample. In some embodiments, memory device 100 may include a differentnumber of device portions, and the circuit elements may be partitionedamong the device portions in a different manner.

In some embodiments, memory device 100 may be formed so as to comprisemultiple semiconductor dice. In this case, device portions 101 through104 of memory device 100 may be distributed among the multiple dice suchthat at least one, but fewer than all of device portions 101 through 104may be formed in each one of the multiple dice. For example, memorycells 121 and associated word lines 115 and bit lines 125 may be formedin one of the multiple dice, and the rest of memory device 100 (e.g.,device portions 102 through 104) may be formed in one or more other diceof the multiple dice. A connection corresponding to at least word lines115, bit lines 125, and signal lines 135 and 145, may be formed amongthe multiple dice to provide communication (e.g. transferring signalsincluding data signals, address signals, control signals, and othersignals) among device portions 101 through 104 or between at least oneof the device portions 101 through 104 and other components that coupledto memory device 100. In some embodiments, memory device 100 may be maybe formed from multiple dice in which the multiple die may be arrangedin a stack.

FIG. 2 shows a partial cross section of an embodiment of an IC package200 having a memory device 203 with portions of memory device 203 beingdistributed in a stack of two dice 201 and 202. Memory device 203 may besimilar to or identical to memory device 100 shown in FIG. 1.

For ease of following the description of the drawings in thisdisclosure, the features in the drawings may be shown in exaggerateddimensions. Further, for clarity, some or all features of a device(e.g., memory device 203) shown in the drawings herein may not havesection line symbols (cross-hatch lines) when the features of the deviceare shown in a cross section view. In FIG. 2, die 201 includes a circuit210 with circuit elements 211. Die 202 includes a circuit 220 withcircuit elements 222. Joints 238 and conductive paths 215 may be coupledto circuits 210 and 220. FIG. 2 shows that at least one of conductivepaths 215 passes through die 202 and may be coupled to at least one ofjoints 238.

Each joint 238 may be located between dice 201 and 202. Joint 238 mayinclude two bond pads 212 and an electrically conductive adhesivematerial 214. In some embodiments, adhesive material 214 may be solder.At least one of bond pads 212 may include multiple layers. In someembodiments, the multiple layers of bond pads 212 may include one ormore layers of a refractory metal, a layer of nickel, a layer of copper,and a layer of gold, alone or in any combination.

IC package 200 may include a support 240 coupled to memory device 203.Support 240 may comprise a ceramic or organic package substrate.Contacts 250 may be coupled to support 240 to enable communication toand from memory device 203. IC package 200 may further include anenclosure 260, which encloses at least a portion of support 240 andmemory device 203, located in an interior 262. In some embodiments,interior 262 may be filled with a filling material, a gas, a liquid, ora combination thereof. The filling material may include a polymermaterial. The gas may include hydrogen, helium, or a mixture of hydrogenand helium. The gas may have a pressure greater than a pressure outsideIC package 200. The liquid may include an organic liquid, such as carbontetrachloride.

In FIG. 2, dice 201 and 202 may include semiconductor material (e.g.,silicon). In some embodiments, dice 201 and 202 may be formed fromdifferent types of wafers. For example, die 201 may be formed from abulk silicon wafer, and die 202 may be formed from asilicon-on-insulator (SOI) wafer. An example of a bulk silicon waferincludes a single crystal silicon wafer. Examples of an SOI waferinclude silicon-on-silicon oxide wafers and silicon-on-sapphire wafers.

In some embodiments, using different materials for dice 201 and 202 mayimprove the performance of memory device 203. For example, in memorydevice 203, when only die 201 includes support circuitry such as a senseamplifier (e.g., sense amplifier 122 of FIG. 1), die 201 may be formedfrom a SOI wafer instead of from a bulk silicon wafer because, incomparison to a bulk silicon wafer, an SOI wafer may cause lessparasitic capacitance in the circuit elements of the sense amplifier. Inanother example, in memory device 203, when only die 202 includes memorycells, such as memory cells 121 of FIG. 1, die 202 may be formed from abulk silicon wafer instead of from a SOI wafer because the floating bodyeffects of the SOI wafer may affect the operation of the memory cells.

As shown in FIG. 2, device portions (e.g., circuits 210 and 220) ofmemory device 203 are distributed among multiple dice (e.g., dice 201and 202), as has been described with respect to device portions 101-104of FIG. 1. In some embodiments, circuit elements 211 of circuit 210 mayinclude memory cells, and circuit elements 222 of circuit 220 mayinclude support circuitry such as decoders, sense amplifiers, one ormore control units, and other circuitry of a functional memory device.Thus, as shown in FIG. 2, the memory cells of memory device 203 may beformed in only circuit 210 of die 201 whereas other circuitry of memorydevice 203 may be formed only in circuit 220 of die 202. Since each ofcircuits 210 and 220 may include only a portion of memory device 203,each of circuits 210 and 220 may be configured to perform only a portionand not the entire function of memory device 203. For example, circuit210 of memory device 203 may be configured to perform only the functionof holding data in memory cells of circuit 210, and circuit 220 ofmemory device 203 may be configured to perform a function of at leastone of decoding function, a sensing function, data input and outputfunctions, and other functions of a memory device.

As shown in FIG. 2, dice 201 and 202 may be stacked vertically on, orwith respect to support 240. In other words, dice 201 and 202 may bestacked in a direction perpendicular to support 240. In comparison witha conventional memory device where all device portions are formed in asingle die with a given dimension, the stacked arrangement of dice 201and 202 of memory device 203, as shown in FIG. 2, may increase thestorage density of memory device 203 for a given volume.

FIG. 2 shows an embodiment of an IC package 200 in which memory device203 is arranged in a so-called a “flip chip” arrangement. In someembodiments, memory device 203 may have other arrangements within ICpackage 200.

FIG. 3 shows a partial cross section of an embodiment of an IC package300 having a memory device 303 in a package with bonding wires. Forclarity, IC package 300 is shown without an enclosure such as enclosure260 of IC package 200 of FIG. 2. In FIG. 3, it can be seen that ICpackage 300 may include one or more memory devices 303 having multipledice (e.g., die 301, die 302), and bonding wires 313 coupled to contacts351 on a support 340. Communication to and from memory device 303 may beconducted through contacts 351. Die 301 may include circuit 310 withcircuit elements 311. Die 302 may include circuit 320 with circuitelements 322. Joints 338 may be located between dice 301 and 302. Insome embodiments, bonding wires 313 may be coupled to contacts 351 fromjoints 338 instead of from the top of die 302 as shown in FIG. 3. Thus,in these embodiments, some or all of the conductive paths 315 may passthrough circuit 310 from joints 338, but not necessarily through die 302to surface 337 of die 302.

FIG. 4 shows a partial cross section of an embodiment of a memory device400 having a stack of more than two dice. Memory device 400 may besimilar to or identical to memory device 203 of FIG. 2 or memory device303 of FIG. 3, except with respect to the number of dice. In FIG. 4,memory device 400 includes multiple dice 401, 402, 403, 404, and 405arranged in a stack. Dice 401 through 405 may be formed from differentwafers. FIG. 4 shows dice 401 through 405 without a package. However, itshould be noted that dice 401 through 405 may be enclosed in an ICpackage such as IC package 200 or 300 or other types of IC packages. InFIG. 4, each of dice 401 through 405 may include one or more of thecorresponding circuits 410, 420, 430, 440, and 450. Dice 401 through 405may be grouped into a first die group 471 and a second die group 472.FIG. 4 shows an example where die group 471 includes three dice 401,402, and 403 and die group 472 includes two dice 404 and 405. In someembodiments, the number of dice within each of die groups 471 and 472may vary. For example, die group 471 may include four dice and die group472 may include only one die. Many other arrangements are possible.

Each of die groups 471 and 472 may include one or more portions ofmemory device 400. In some embodiments, the memory cell portion ofmemory device 400 may be included in only circuits 410, 420, and 430 ofdie group 471, and other device portions (e.g. decoder, sense amplifier,and control unit) of memory device 400 may be included in only circuits440 and 450 of die group 472. In other embodiments, other combinationsof the device portions of memory device 400 may be formed on andpartitioned among die groups 471 and 472.

FIG. 4 shows memory device 400 having five dice as an example. In someembodiments, the total number of dice in memory device 400, the numberof dice in each of die groups 471 and 472, or both, may vary. Asdescribed above, memory device 203, 303, and 400 in FIG. 2, FIG. 3, andFIG. 4 may be formed from different types of semiconductor wafers (e.g.,bulk and/or SOI wafers, among others).

FIG. 5 and FIG. 6 show different views of an embodiment of a wafer 500with dice having portions of memory devices. FIG. 5 shows a plan view ofwafer 500. FIG. 6 shows a partial cross section of a portion of wafer500, which may be made from semiconductor material (e.g., silicon). Insome embodiments, wafer 500 may include a bulk silicon wafer. As shownin FIG. 5 and FIG. 6, wafer 500 includes a plurality of dice 501, andgrooves 588. In some embodiments, grooves 588 may be formed by partiallyscribing or cutting wafer 500 from surface 617 (FIG. 6) of wafer 500 tosome selected depth 619. As shown in FIG. 6, wafer portion 699 of wafer500 holds the dice 501 together. The dice 501 may be separated from eachother when wafer portion 699 is removed.

Each die 501 may include one or more circuits 510, conductive paths 615,bond pads 612, and adhesive materials 514. The circuits 510 may includecircuit elements (e.g., memory cells, sense amplifiers, decoders), whichare not shown in FIG. 5 and FIG. 6 for clarity. Conductive paths 615(FIG. 6), which extend substantially perpendicularly from surface 617 ofwafer 500 to some selected depth 619 within circuit 510, may provideconnections and communications to and from circuit 510. In someembodiments, conductive paths 615 may include word lines and bit linesof memory device, such as word lines 115 and bit lines 125 of memorydevice 100 of FIG. 1.

In FIG. 5 and FIG. 6, adhesive materials 514 of die 501 may allowattachment or bonding of conductive paths 615 to other components. Insome embodiments, adhesive materials 514 may include solder balls orsolder bumps.

A portion of a memory device (e.g., memory device 100, 203, 303, or 400of FIG. 1 through FIG. 4) may be formed in each die 501 such thatcircuit 510 of each die 501 may contain circuit elements of only aportion of the memory device. For example, a device portion containingmemory cells of a memory device may be formed in each die 501 of wafer500. Other device portions of the memory device (e.g., sense amplifiers,decoders, or both) may be formed in another wafer different from wafer500.

FIG. 7 and FIG. 8 show different views of an embodiment of a wafer 700with dice having other device portions of memory devices. FIG. 7 shows aplan view of wafer 700. FIG. 8 shows a partial cross section of a partof wafer 700, which may be made from semiconductor material (e.g.,silicon). In some embodiments, wafer 700 may include an SOI wafer. Asshown in FIG. 7 and FIG. 8, wafer 700 includes a plurality of dice 701,and grooves 788 extending from a surface 817 of wafer 700 to someselected depth 819. As shown in FIG. 8, a wafer portion 899 of wafer 700holds dice 701 together. Dice 701 may be separated from each other whenwafer portion 899 is removed.

Each die 701 of wafer 700 may include one or more circuits 710,conductive paths 815, and bond pads 812. In some embodiments, each die701 may include adhesive materials, such as the adhesive material 714,on bond pads 812. Circuit 710 may include circuit elements (e.g., memorycells, sense amplifiers, decoders), which are not shown in FIG. 7 andFIG. 8 for clarity. Conductive paths 815 may provide connections andcommunication to and from circuit 710. In some embodiments, conductivepaths 815 may include connections (e.g., bit lines 125 of FIG. 1)between memory cells of a memory device and sense amplifiers, orconnections between memory cells and decoders (e.g., the word lines 115of FIG. 1) of the memory device. In FIG. 8, conductive paths 815 extendsubstantially perpendicularly from surface 817 of wafer 700 throughcircuit 710 to some selected depth 829. Relative to surface 817, depth829 may be greater than depth 819. Thus, when wafer portion 899 isremoved, end portions 818 of conductive paths 815 may be exposed. Otherconnections may be coupled to conductive path 815 at exposed endportions 818 so that circuit 710 may communicate with other componentsthrough connections from both sides of die 701: one side at end portions818 and the other side at bond pads 812. Thus, each die 701 may have aconductive path passing through die 701 from one surface (surface 817)to another surface (surface at depth 819 when wafer portion 899 isremoved). In some embodiments, conductive paths 815 passing through die701 of FIG. 8 may be similar to or identical to conductive path 215passing through die 202 of FIG. 2.

In FIG. 7 and FIG. 8, a portion of a memory device (e.g., memory device203, 303, or 400) may be formed in each die 701 such that circuit 710 ofeach die 701 may contain circuit elements of only a portion of thememory device. For example, a device portion containing senseamplifiers, decoders, or both sense amplifiers and decoders of a memorydevice may be formed in each die 701 of wafer 700. Other dice portionsof the memory device (e.g., memory cells) may be formed in another waferdifferent from wafer 700 (e.g., wafer 500 of FIG. 5).

As described above in reference to FIG. 5 through FIG. 8, each die 501of wafer 500 or each die 701 of wafer 700 may include only a portion ofa memory device (e.g., memory cells, sense amplifiers, decoders, orcontrol unit or a combination of some but not all of these circuitelements). Thus, each die 501 itself or each die 701 itself may containan incomplete or a non-functional memory device. However, thecombination of one die 501 of wafer 500 and one die 701 of wafer 700 mayform a complete or a functional memory device. In some embodiments, dice501 and 701 may have a substantially equal size to improve alignmentbetween dice 501 and 701 when they are combined. In some embodiments, atleast one wafer 500 of FIG. 5 and at least one wafer 700 of FIG. 7 maybe combined at wafer level in a wafer stack to form a number of completememory devices.

FIG. 9 shows an exploded view of an embodiment of a wafer stack 900having dice 906 with substantially the same size. For clarity, in FIG.9, only wafer 931 is shown with multiple dice 906. Each of wafers 932,933, 934, 935, and 936 also includes multiple dice. Dice 906 of wafers931 through 936 have a substantially equal size. The substantially equalsize is represented in FIG. 9 as dimension 909, which is determined froma plan view (top view) seen from a direction 999. Dimension 909 maycomprise a length dimension, a width dimension, an area dimension, or asum of the length and widths for an area. Substantially equality in sizemay allow ease of feature alignment (e.g., bond pads such as bond pads612 or 812 in FIG. 6 or FIG. 8, respectively) among dice 906 in waferstack 900 when dice 906 are combined during processes of forming adevice, such as memory device 100, 203, 303, and 400 of FIG. 1 throughFIG. 4.

FIG. 10 through FIG. 20 show processes of forming a memory device from awafer stack of two wafers according to various embodiments of theinvention.

FIG. 10 shows a cross section of a wafer 1000, having three dice 1001 asan example. Wafer 1000 may have a different number of dice. In someembodiments, wafer 1000 includes embodiments of wafers 500, 700, andwafers 931 through 936 of FIG. 5 through FIG. 9. In FIG. 10, wafer 1000includes a wafer portion 1099, and a number of grooves 1088 extendingfrom the wafer surface 1017 to a selected depth 1019. In a subsequentprocess, dice 1001 may be separated from each other when wafer portion1099 is removed. In some embodiments, wafer portion 1099 may be removedby wafer thinning or by grinding a surface (or back side) 1037 of wafer1000.

In FIG. 10, each die 1001 may include one or more circuits 1010,conductive paths 1015, bond pads 1012, and adhesive materials 1014.Adhesive materials 1014 may include solder. In some embodiments, bondpads 1012 and adhesive materials 1014 of die 1001 may be formed usingtechniques described in U.S. Pat. Nos. 6,136,689 and 6,958,287,incorporated herein by reference in their entirety.

Circuit 1010 may include a portion of a memory device (e.g., similar toor identical to device portion 101 with memory cells 121 of memorydevice 100 of FIG. 1) such that circuit 1010 is configured to performonly a portion of a function of a memory device. For example, circuit1010 may include at least one but fewer than all of the following:memory cells and associated word lines and bit lines, a decoder, a senseamplifier, a control unit, input/output unit, and other circuitry of amemory device. Thus, in some embodiments, circuit 1010 of die 1001 mayinclude memory cells and associated word lines and bit lines of a memorydevice without additional circuitry (e.g., without a decoder, a senseamplifier, or both) of the memory device. The additional circuitry ofthe memory device may be formed in another die of another wafer or inmultiple dice of multiple wafers.

FIG. 11 shows a partial cross section of a wafer 1100 including threedice 1102 as an example. Wafer 1100 may have a different number of dice.In some embodiments, wafer 1100 includes embodiments of wafers 500, 700,and wafers 931 through 936 of FIG. 5 through FIG. 9. In FIG. 11, wafer1100 includes a wafer portion 1199, which holds dice 1102 together, andgrooves 1188 extending from wafer surface 1117 to a selected depth 1119.Dice 1102 may be separated from each other when wafer portion 1199 isremoved. In some embodiments, wafer portion 1199 may be removed bygrinding a surface (or back side) 1137 of wafer 1100.

In FIG. 11, each die 1102 may include one or more circuits 1110, bondpads 1112, and conductive paths 1115. Each conductive path 1115 may becoupled to one bond pad 1112, so as to extend from wafer surface 1117 toa selected depth 1129. Each conductive path 1115 may include an endportion 1118, which may be exposed when wafer portion 1199 is removed.In some embodiments, conductive paths 1115 may be formed usingtechniques described in U.S. Pat. Nos. 5,202,754; 5,892,288; and6,507,117; each of which is incorporated herein by reference in itsentirety. FIG. 11 shows bond pads 1112 without adhesive materials (e.g.,solder). In some embodiments, adhesive materials may also be formed onbond pads 1112.

In FIG. 11, the circuits 1110 may include a portion of a memory device(e.g., similar to or identical to the portion 103 of memory device 100of FIG. 1) such that circuit 1110 is configured to perform only aportion of a function of the memory device. For example, circuit 1110may include at least one but fewer than all of the following: memorycells and associated word lines and bit lines, a decoder, a senseamplifier, a control unit, input/output unit, and other circuitry for amemory device. Thus, in some embodiments, circuit 1110 of die 1102 mayinclude at least one of a decoder, a sense amplifier, a control unit,input/output unit, and other circuitry for a memory device withoutadditional circuitry (e.g., without memory cells and associated wordlines and bit lines) of the memory device. The additional circuitry ofthe memory device may be formed in another die of another wafer (e.g.,wafer 1000 of FIG. 10) or in multiple dice of multiple wafers.

FIG. 12 shows wafer 100 of FIG. 11 being contacted or combined withwafer 1000 such that bond pads 1112 of wafer 1100 are substantiallyaligned and in contact with corresponding bond pads 1012 of wafer 1000.FIG. 12 shows wafer 1100 being placed on wafer 1000 as an example. Insome embodiments, wafer 1000 may be placed on wafer 1100.

FIG. 13 shows wafers 1000 and 1100 after a bonding process has beenperformed. In some embodiments, wafers 1000 and 1100 may be put througha bonding process to cause adhesive materials 1014 to couple bond pads1012 to bond pads 1112 to form a number of joints 1338 between dice 1001and dice 1102. In some embodiments, adhesive materials 1014 may includesolder such that wafers 1000 and 1100 may be put through a solder reflowprocess to cause the solder to melt and then solidify such that joints1338 comprise solder joints. The solder reflow process may be a C4(controlled collapsed chip connection) process. Thus, in someembodiments, joints 1338 comprise C4 solder joints. It should be notedthat joints 238 of FIG. 2, joints 338 of FIG. 3, joints 1338 of FIG. 13,and all similarly and subsequently described joints herein may compriseelectrically conductive joints.

In FIG. 13, each die 1001 of wafer 1000 and each die 1102 of wafer 1100may form a die combination such as die combinations 1381, 1382, or 1383.FIG. 13 shows die combinations 1381, 1382, and 1383 being held togetherby wafer portions 1099 and 1199. In a subsequent process, diecombinations 1381, 1382, and 1383 may be separated from each other intosingle die combinations when wafer portions 1099 and 1199 are removed.In some embodiments, any one or more of die combinations 1381, 1382, and1383, after being separated from each other, may form a functionalmemory device similar to or identical to memory device 203 of FIG. 2 ormemory device 303 of FIG. 3.

FIG. 14 shows the wafer 1100 after wafer portion 1199 (see FIG. 13) ofthe wafer 1100 is removed. In FIG. 14, dice 1102 are separated from eachother but remain bonded to dice 1001 of wafer 1000. End portion 1118 ofeach conductive path 1115 may be exposed on die surface 1418 of each die1102.

FIG. 15 shows dice 1102 with bond pads 1512 and adhesive materials 1514formed over end portions 1118 of conductive paths 1115.

FIG. 16 shows a holder 1641 coupled to wafer 1100. Holder 1641 may beused to temporarily hold die combinations 1381, 1382, and 1383 so thatwafer portion 1099 of wafer 1000 may be removed to separate dice 1001from each other.

FIG. 17 shows die combinations 1381, 1382, and 1383 being separated fromeach other after wafer portion 1099 of wafer 1000 (see FIG. 16) isremoved.

FIG. 18 shows die combinations 1381, 1382, and 1383 after holder 1641(see FIG. 16) is removed. Each of die combinations 1381, 1382, and 1383may form an individual, functional memory device. Packaging processesmay be performed to enclose each of die combinations 1381, 1382, and1383 in an IC package, similar to or identical to an IC package 200(FIG. 2), an IC package 300 (FIG. 3), or other types of IC packages. Insome embodiments, testing of die combinations 1381, 1382, and 1383 maybe performed at the wafer level (e.g. during the processes correspondingto FIG. 16 or FIG. 17) or at the device level (e.g., during or after theprocesses corresponding to FIG. 18).

FIG. 19 shows a die 1902 being removed from a die combination. Diecombinations 1981, 1982, and 1983 of FIG. 19 may include embodiments ofdie combinations 1381, 1382, and 1383 that arise during theimplementation of the processes described in reference to FIG. 10through FIG. 18. In FIG. 19, the die 1902 is removed from diecombination 1983 so that a non-defective die (i.e., a good die) mayreplace die 1902 determined to be defective, perhaps during a testingprocess.

Testing of die 1902 may be performed before or after die 1902 is bondedto dice 1901 of wafer 1900. For example, die 1902 may be tested while itis on wafer 1950, before wafer 1950 is bonded to wafer 1900. During thetesting of die 1902, the location identification (ID), such as X-Ycoordinates, of die 1902 may be recorded when die 1902 is determined tobe defective. In FIG. 19, based on the recorded ID, die 1902 may belocated, removed, and replaced after wafer 1950 is bonded to wafer 1900.In some embodiments, removing die 1902 may involve a technique describedin U.S. Pat. No. 4,923,521, hereinafter incorporated by reference in itsentirety.

In some embodiments, adhesive materials 1914 may be omitted from die1901 during the processes of forming die combinations 1981, 1982, and1983 when a corresponding die such as die 1902 is previously determinedor known to be defective. By refraining from adding the adhesivematerial to, or omitting the adhesive material from die 1901, adefective die such as die 1902 may not be bonded to die 1901 when diecombinations 1981, 1982, and 1983 are formed, thereby simplifyingremoval of a defective die such as die 1902 from die combination 1983.

In some embodiments, die 1902 may include redundancy circuit elementsfor replacing defective circuit elements. During testing, the redundancycircuit elements in die 1902 may be used to replace defective circuitelements, repairing defective die 1902 such that defective die 1902 maybecome a good die, perhaps obviating removal of die 1902 from diecombination 1983. In some embodiments, even if die 1902 is defective,the removal of die 1902 from die combination 1983 may be omitted. Inaddition, or alternatively, die combination 1983 that contains defectivedie 1902 may be determined to be defective (perhaps due to the existenceof defective die 1902, or for other reasons) and may be discarded afterdie combination 1983 is separated from die combinations 1981 and 1982.

FIG. 20 shows a non-defective die 2002 that is used to replace defectivedie 1902 (see FIG. 19). In FIG. 20, die 2002 may be bonded to die 1901by implementing a selected bonding process. In some embodiments, toreduce thermal effects on the connections of non-defective diecombinations 1981 and 1982, a localized reflow process may be preformedsuch that only a selected area in the proximity of die combination 1983is heated to a temperature higher than the areas proximate tonon-defective die combinations 1981 and 1982. After the replacement ofthe defective die in FIG. 20, die combinations 1981, 1982, and 1983 maythen be separated from each other by processes similar to that describedin reference to FIG. 15 through FIG. 18.

FIG. 10 through FIG. 20 show processes of forming a memory device from awafer stack of two wafers as an example. In some embodiments, a memorydevice may be formed from a wafer stack of more than two wafers usingprocesses similar to or identical to the processes described inreference to FIG. 10 through FIG. 20.

FIG. 21 and FIG. 22 show processes of forming a memory device from awafer stack of more than two wafers. FIG. 21 shows an example of a waferstack 2100 having five wafers 2131, 2132, 2133, 2134, and 2135. In someembodiments, wafer stack 2100 may have a different number of wafers.FIG. 21 shows dice 2101, 2102, 2103, 2104, and 2105 have a substantialequal size. In some embodiments, the size and shape of dice 2101, 2102,2013, 2104, and 2105 may be different among each other. In FIG. 21, dice2101, 2102, 2013, 2104, and 2105 of die combinations 2181, 2182, and2183 may be formed using processes similar to or identical to thosedescribed in reference to FIG. 10 through FIG. 20. For example, afterwafers 2131 and 2132 are bonded to each other, wafer 2133 may be bondedto wafer 2132, then wafer 2134 may be bonded to wafer 2133, and thenwafer 2135 may be bonded to wafer 2134.

FIG. 22 shows die combinations 2181, 2182, and 2183 of FIG. 21 afterthey have been separated. Each of die combinations 2181, 2182, and 2183may form a separate, functional memory device in which each of dice 2101through 2105 may form a portion of the individual memory devices. Forexample, in each of die combinations 2181, 2182, and 2183, memory cellsof the memory device may be formed in only dice 2101, 2102, and 2103 andthe rest of the circuitry of the respective memory devices may be formedin dice 2104 and 2105. Packaging processes may be performed to encloseeach of combinations 2181, 2182, and 2183 in one or more IC packages,similar to or identical to IC package 200 (FIG. 2), IC package 300 (FIG.3), or other types of IC packages.

FIG. 23 through FIG. 26 show processes of forming a memory device frommultiple wafer stacks. In FIG. 23 a first wafer stack 2300 includeswafers 2331, 2332, 2333, and 2334 with die combinations 2381, 2382, and2383. In FIG. 24 a second wafer stack 2400 includes wafers 2431, 2432,and 2433 with die combinations 2481, 2482, and 2483. Die combinations ineach of wafer stacks 2300 and 2400 may be formed using processes similarto or identical to those described in FIG. 10 through FIG. 22.

FIG. 25 shows wafer stack 2300 of FIG. 23 and wafer stack 2400 of FIG.24 being bonded together to produce die combinations 2581, 2582, and2583.

FIG. 26 shows die combinations 2581, 2582, and 2583 after they have beenseparated from each other. Each of die combinations 2581, 2582, and 2583may include one of the die combinations of wafer stack 2300 and one ofthe die combinations of wafer stack 2400. Each of die combinations 2581,2582, and 2583 may form a separate, functional memory device. Packagingprocesses may be performed to enclose each of combinations 2581, 2582,and 2583 in one or more IC packages, similar to or identical to ICpackage 200 (FIG. 2), IC package 300 (FIG. 3), or other types of ICpackages.

FIG. 27 and FIG. 28 show processes of forming a device from a waferstack 2700 in which at least one wafer of wafer stack 2700 includesmultiple circuits in each die. FIG. 27 shows an example of wafer stack2700 having three wafers 2731, 2732, and 2733. In some embodiments,wafer stack 2700 may have a different number of wafers. In FIG. 27, dice2701, 2702, and 2703 of die combinations 2781 and 2782 may be formedusing processes similar to those described in reference to FIG. 10through FIG. 26. In FIG. 27 each die 2701 of wafer 2731 may include twocircuits 2710. In wafer 2732, each die 2702 may include one circuit2720. In wafer 2733, each die 2703 may include two circuits 2730.

A link (e.g., link 2745 or 2755) may be formed to allow the circuitswithin dice 2701 and 2703 to communicate with each other. FIG. 27 showseach die 2701 being coupled to a pair of dice 2702. In some embodiments,wafer stack 2700 may have other arrangements different from that shownin FIG. 27. For example, the pair of dice 2702 in FIG. 27 may becombined into a single die such as die 2701. For another example, eachdie 2703 linked by the link 2755 may be separated to form a pair ofseparated dice, such as dice 2702. Other combinations, including threeand more dice linked together are possible.

FIG. 28 shows die combinations 2781 and 2782 of FIG. 27 after they havebeen separated from each other. Each of die combinations 2781 and 2782may form a functional device in which each of dice 2701, 2702 and 2703may form a portion of the device that is non-functional without beingcoupled to the other portions.

In some embodiments, each of die combinations 2781 and 2782 of FIG. 28may form a memory device such that memory cells of the memory device maybe formed in at least one but fewer than all of dice 2701, 2702, and2703 and the rest of the circuitry of the memory device may be formed inthe rest of dice 2701, 2702, and 2703.

In other embodiments, each of die combinations 2781 and 2782 of FIG. 28may form a processor with single or multiple processing cores (i.e., amultiple-core processor) such that logic circuitry of the processor maybe formed in at least one but fewer than all of dice 2701, 2702, and2703 and the rest of the circuitry of the processor may be formed in therest of dice 2701, 2702, and 2703. For example, each of the multipleprocessing cores of the processor may be formed in one of dice 2701 andother circuitry of the processor may be formed in one or more of dice2702 and 2703.

In some embodiments, each of die combinations 2781 and 2782 of FIG. 28may form a system on a chip such that one or more processor logiccircuitry sections (e.g., one or more processing cores) for a processormay be formed in at least one but fewer than all dice 2701, 2702, and2703. One or more memory devices (e.g., DRAM, SRAM cache, or both) maybe formed in dice 2701, 2702, and 2703 that are separated from the dieor dice where the logic circuitry of the processor is formed.

FIG. 28 shows each of die combinations 2781 and 2782 in an unpackagedform. Packaging processes may be performed to enclose each of diecombinations 2781 and 2782 in one or more IC packages.

FIG. 29 shows a block diagram of an IC package 2900. IC package 2900includes a memory device 2903, a processor 2904, and a connection 2915.Memory device 2903 may include memory cells 2910 and support circuitry2920. Processor 2904 may include multiple processing cores 2930 and2940. Thus, processor 2904 may comprise a multiple-core processor.Processing core 2930 may include an arithmetic logic unit (ALU) 2931 andadditional circuitry 2932. Processing core 2940 may also include an ALU2941 and additional circuitry 2942. ALU 2931 and ALU 2941 may performmathematic functions such as addition and subtraction. Additionalcircuitry 2932 and 2942 may perform other tasks of processor 2904. Insome embodiments, processor 2904 may omit one of cores 2930 and 2940such that processor 2904 may comprise a single core processor. In otherembodiments, IC package 2900 may omit memory device 2903 and processor2904 may be formed in multiple dice in which device portions (e.g.,logic circuitry) of processor 2904 may be distributed among the multipledice such that one of the dice may include ALU 2931, and another die mayinclude ALU 2941.

In some embodiments, the circuitry included in IC package 2900 may beformed in two or more separate dice. For example, memory cells 2910, andsupport circuitry 2920 may be formed on two or more separate dice, andprocessing cores 2930 and 2940 may be formed in at least one die. ICpackage 2900 may include or implement any of the embodiments describedabove in reference to FIG. 2 through FIG. 28.

FIG. 30 shows a block diagram of a system 3000 according to anembodiment of the invention. System 3000 may include one or moreprocessors 3010, memory devices 3020, memory controllers 3030, graphicscontrollers 3040, input and output (I/O) controllers 3050, displays3052, keyboards 3054, pointing devices 3056, peripheral devices 3058,and buses 3060.

Processor 3010 may comprise a general-purpose processor or anapplication specific integrated circuit (ASIC), which may include asingle-core processor or a multiple-core processor. Memory device 3020may comprise a DRAM device, an SRAM device, a flash memory device, or acombination of these memory devices. The I/O controller 3050 may includea communication module for wired or wireless communication.

One or more of the components shown in system 3000 may be included in asingle IC package. FIG. 30 shows an example where two components,processor 3010 and memory device 3020, may be included in a single ICpackage such as IC package 3080. Any one or more or the components shownin system 3000 may include embodiments of FIG. 1 through FIG. 29.

System 3000 may include computers (e.g., desktops, laptops, hand-helds,servers, web appliances, routers, etc.), wireless communication devices(e.g., cellular phones, cordless phones, pagers, personal digitalassistants, etc.), computer-related peripherals (e.g., printers,scanners, monitors, etc.), entertainment devices (e.g., televisions,radios, stereos, tape and compact disc players, video cassetterecorders, camcorders, digital cameras, MP3 (Motion Picture ExpertsGroup, Audio Layer 3) players, video games, watches, etc.), and thelike.

The above description and the drawings illustrate some exampleembodiments of the invention. Other embodiments may incorporatestructural, logical, electrical, process, and other changes. In thedrawings, like features or like numerals describe substantially similarfeatures. Examples merely show possible variations. Portions andfeatures of some embodiments may be included in, or substituted for,those of others. Many other embodiments will be apparent to those ofskill in the art upon reading and understanding the above description.Therefore, the scope of various embodiments of the present disclosure isdetermined by the appended claims, along with the full range ofequivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred toherein individually or collectively by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single invention or inventive concept, if more thanone is in fact disclosed. Thus, although specific embodiments have beenillustrated and described herein, any arrangement calculated to achievethe same purpose may be substituted for the specific embodiments shown.This disclosure is intended to cover any and all adaptations orvariations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,will be apparent to those of skill in the art upon reviewing the abovedescription.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted to require morefeatures than are expressly recited in each claim. Rather, inventivesubject matter may be found in less than all features of a singledisclosed embodiment. Thus the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment.

1. A memory device comprising: a first die having a first circuit; asecond die having a second circuit; a third die having a third circuit;wherein the first die, second die, and third die are arranged in astack; only the first circuit and the second circuit include a pluralityof memory cells, wherein the memory cells of the first circuit and thememory cells of the second circuit are coupled together via a pluralityof word line and bit lines, and only the third circuit includes a senseamplifier coupled to said memory cells.
 2. The memory device of claim 1,wherein only the second circuit includes a decoder coupled to the memorycells.
 3. The memory device of claim 2, wherein the word lines arecoupled to the decoder via a plurality of solder joints.
 4. The memorydevice of claim 1, wherein the first die includes a plurality of firstbond pads coupled to the first circuit, and wherein at least one of theplurality of first bond pads includes a stack of multiple layers.
 5. Thememory device of claim 1, wherein the first die and the second die areenclosed in an integrated circuit package.
 6. The memory device of claim5, wherein a space between the first die and the second die is filledwith one of a gas and a liquid.
 7. The memory device of claim 6, whereinthe gas has a pressure greater than a pressure outside the integratedcircuit package.
 8. The memory device of claim 4, wherein the stack ofmultiple layers includes at least one of a layer of a refractory metal,a layer of nickel, a layer of copper, and a layer of gold.
 9. The memorydevice of claim 8, wherein the second die includes a plurality of secondbond pads coupled to the second circuit, and wherein at least one of thesecond bond pads includes a stack of multiple layers.
 10. The memorydevice of claim 4, wherein one of the first bond pads forms part of ajoint located between the first and second dice.
 11. The memory deviceof claim 10, wherein the joint includes solder.
 12. The memory device ofclaim 1, wherein first die is included in a first device portion of aplurality of device portions of the memory device, the second die isincluded in a second device portion of the plurality of device portions,and each of the first and second device portions includes fewer than allof the plurality of memory cells, a decoder, a sense amplifier, and acontrol unit of the memory device.
 13. The memory device of claim 1,wherein the word lines and the bit lines comprise parts of conductivepaths that extend through the first die from a first surface of thefirst die to a second surface of the first die.
 14. The memory device ofclaim 1, wherein the word lines and the bit lines comprise parts ofconductive paths that extend through the second die from a first surfaceof the second die to a second surface of the second die.
 15. A memorydevice comprising: a first die having a first circuit; a second diehaving a second circuit; a third die having a third circuit; wherein thefirst die, second die, and third die are arranged in a stack; only thefirst circuit and the second circuit include a plurality of memorycells, wherein the memory cells of the first circuit and the memorycells of the second circuit are coupled together via a plurality of wordline and bit lines, and only the third circuit includes a senseamplifier coupled to said memory cells, and the bit lines are coupled tothe sense amplifier via a plurality of solder joints.
 16. A memorydevice comprising: a first die having a first circuit; a second diehaving a second circuit; a third die having a third circuit; wherein thefirst die, second die, and third die are arranged in a stack; only thefirst circuit and the second circuit include a plurality of memorycells, wherein the memory cells of the first circuit and the memorycells of the second circuit are coupled together via a plurality of wordline and bit lines, and only the third circuit includes a senseamplifier coupled to said memory cells, wherein the first die includes asemiconductor wafer material of a first wafer type, wherein the seconddie includes a semiconductor wafer material of a second wafer type, andwherein the first wafer type comprises a bulk silicon wafer type, andwherein the second wafer type comprises a silicon-on-insulator wafertype.